diff mbox series

[3/3] vhost-user: return failure if backend crash when live migration

Message ID 20250309094051.3655292-2-haoqian.he@smartx.com (mailing list archive)
State New
Headers show
Series vhost: fix the IO error after live migration | expand

Commit Message

Haoqian He March 9, 2025, 9:40 a.m. UTC 
Live migration should be terminated if backend crash.

Since the vhost device will be stopped when VM is stopped before
the end of the live migration, current implementation if vhost
backend died, vhost device's set_status() will not return failure,
live migration won't perceive the disconnection between qemu and
vhost backend, inflight io would be submitted in migration target
host, leading to IO error.

To fix this issue:
1. Add set_status_ext() which has return value for
VirtioDeviceClass and vhost-user-blk/scsi use the _ext version.

2. In set_status_ext(), return failure if the flag `connected`
is false or vhost_dev_stop return failure, which means qemu lost
connection with backend.

Hence migration_completion() will process failure, terminate
migration and restore VM.

Signed-off-by: Haoqian He <haoqian.he@smartx.com>
---
 hw/block/vhost-user-blk.c             | 29 +++++++++++++++------------
 hw/scsi/vhost-scsi-common.c           | 11 +++++-----
 hw/scsi/vhost-user-scsi.c             | 20 ++++++++++--------
 hw/virtio/virtio.c                    | 20 +++++++++++++-----
 include/hw/virtio/vhost-scsi-common.h |  2 +-
 include/hw/virtio/virtio.h            |  1 +
 6 files changed, 51 insertions(+), 32 deletions(-)

Comments

Raphael Norwitz March 9, 2025, 4:30 p.m. UTC | #1 
I'll let others chime in on higher level device model changes you're
making. For the vhost-user-blk and vhost-user-scsi bits:

On Sun, Mar 9, 2025 at 11:41 AM Haoqian He <haoqian.he@smartx.com> wrote:
>
> Live migration should be terminated if backend crash.

nit: "...if the backend crashes before the migration completes."

>
> Since the vhost device will be stopped when VM is stopped before
> the end of the live migration, current implementation if vhost
> backend died, vhost device's set_status() will not return failure,
> live migration won't perceive the disconnection between qemu and
> vhost backend, inflight io would be submitted in migration target
> host, leading to IO error.
>
> To fix this issue:
> 1. Add set_status_ext() which has return value for
> VirtioDeviceClass and vhost-user-blk/scsi use the _ext version.
>
> 2. In set_status_ext(), return failure if the flag `connected`
> is false or vhost_dev_stop return failure, which means qemu lost
> connection with backend.

I have some concerns with [2]. See my later responses.

>
> Hence migration_completion() will process failure, terminate
> migration and restore VM.
>
> Signed-off-by: Haoqian He <haoqian.he@smartx.com>
> ---
>  hw/block/vhost-user-blk.c             | 29 +++++++++++++++------------
>  hw/scsi/vhost-scsi-common.c           | 11 +++++-----
>  hw/scsi/vhost-user-scsi.c             | 20 ++++++++++--------
>  hw/virtio/virtio.c                    | 20 +++++++++++++-----
>  include/hw/virtio/vhost-scsi-common.h |  2 +-
>  include/hw/virtio/virtio.h            |  1 +
>  6 files changed, 51 insertions(+), 32 deletions(-)
>
> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
> index ae42327cf8..4865786c54 100644
> --- a/hw/block/vhost-user-blk.c
> +++ b/hw/block/vhost-user-blk.c
> @@ -204,7 +204,7 @@ err_host_notifiers:
>      return ret;
>  }
>
> -static void vhost_user_blk_stop(VirtIODevice *vdev)
> +static int vhost_user_blk_stop(VirtIODevice *vdev)
>  {
>      VHostUserBlk *s = VHOST_USER_BLK(vdev);
>      BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> @@ -212,26 +212,26 @@ static void vhost_user_blk_stop(VirtIODevice *vdev)
>      int ret;
>
>      if (!s->started_vu) {
> -        return;
> +        return 0;
>      }
>      s->started_vu = false;
>
>      if (!k->set_guest_notifiers) {
> -        return;
> +        return 0;
>      }
>
> -    vhost_dev_stop(&s->dev, vdev, true);
> +    ret = vhost_dev_stop(&s->dev, vdev, true);
>
> -    ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
> -    if (ret < 0) {
> +    if (k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false) < 0) {
>          error_report("vhost guest notifier cleanup failed: %d", ret);
> -        return;
> +        return -1;
>      }
>
>      vhost_dev_disable_notifiers(&s->dev, vdev);
> +    return ret;
>  }
>
> -static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostUserBlk *s = VHOST_USER_BLK(vdev);
>      bool should_start = virtio_device_should_start(vdev, status);
> @@ -239,11 +239,11 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
>      int ret;
>

Do we want to fail out in all cases where vhost_user_blk_set_status()
and the device is not connected? Could this impact power-on if the
backend is temporarily down?

>      if (!s->connected) {
> -        return;
> +        return -1;
>      }
>
>      if (vhost_dev_is_started(&s->dev) == should_start) {
> -        return;
> +        return 0;
>      }
>
>      if (should_start) {
> @@ -253,9 +253,12 @@ static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
>              qemu_chr_fe_disconnect(&s->chardev);
>          }
>      } else {
> -        vhost_user_blk_stop(vdev);
> +        ret = vhost_user_blk_stop(vdev);
> +        if (ret < 0) {
> +            return ret;
> +        }
>      }
> -
> +    return 0;
>  }
>
>  static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
> @@ -597,7 +600,7 @@ static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
>      vdc->get_config = vhost_user_blk_update_config;
>      vdc->set_config = vhost_user_blk_set_config;
>      vdc->get_features = vhost_user_blk_get_features;
> -    vdc->set_status = vhost_user_blk_set_status;
> +    vdc->set_status_ext = vhost_user_blk_set_status;
>      vdc->reset = vhost_user_blk_reset;
>      vdc->get_vhost = vhost_user_blk_get_vhost;
>  }
> diff --git a/hw/scsi/vhost-scsi-common.c b/hw/scsi/vhost-scsi-common.c
> index 4c8637045d..bfeed0cb1b 100644
> --- a/hw/scsi/vhost-scsi-common.c
> +++ b/hw/scsi/vhost-scsi-common.c
> @@ -101,24 +101,25 @@ err_host_notifiers:
>      return ret;
>  }
>
> -void vhost_scsi_common_stop(VHostSCSICommon *vsc)
> +int vhost_scsi_common_stop(VHostSCSICommon *vsc)
>  {
>      VirtIODevice *vdev = VIRTIO_DEVICE(vsc);
>      BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
>      VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
>      int ret = 0;
>
> -    vhost_dev_stop(&vsc->dev, vdev, true);
> +    ret = vhost_dev_stop(&vsc->dev, vdev, true);
>
>      if (k->set_guest_notifiers) {
> -        ret = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false);
> -        if (ret < 0) {
> +        int r = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false);
> +        if (r < 0) {
>                  error_report("vhost guest notifier cleanup failed: %d", ret);
>          }

Now that we return back a value the assert here should probably be dropped?

> +        assert(r >= 0);
>      }
> -    assert(ret >= 0);
>
>      vhost_dev_disable_notifiers(&vsc->dev, vdev);
> +    return ret;
>  }
>
>  uint64_t vhost_scsi_common_get_features(VirtIODevice *vdev, uint64_t features,
> diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
> index adb41b9816..8e7efc38f2 100644
> --- a/hw/scsi/vhost-user-scsi.c
> +++ b/hw/scsi/vhost-user-scsi.c
> @@ -52,19 +52,19 @@ static int vhost_user_scsi_start(VHostUserSCSI *s, Error **errp)
>      return ret;
>  }
>
> -static void vhost_user_scsi_stop(VHostUserSCSI *s)
> +static int vhost_user_scsi_stop(VHostUserSCSI *s)
>  {
>      VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
>
>      if (!s->started_vu) {
> -        return;
> +        return 0;
>      }
>      s->started_vu = false;
>
> -    vhost_scsi_common_stop(vsc);
> +    return vhost_scsi_common_stop(vsc);
>  }
>
> -static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
> +static int vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
>  {
>      VHostUserSCSI *s = (VHostUserSCSI *)vdev;
>      DeviceState *dev = DEVICE(vdev);
> @@ -75,11 +75,11 @@ static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
>      int ret;
>
>      if (!s->connected) {
> -        return;
> +        return -1;
>      }
>
>      if (vhost_dev_is_started(&vsc->dev) == should_start) {
> -        return;
> +        return 0;
>      }
>
>      if (should_start) {
> @@ -91,8 +91,12 @@ static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
>              qemu_chr_fe_disconnect(&vs->conf.chardev);
>          }
>      } else {
> -        vhost_user_scsi_stop(s);
> +        ret = vhost_user_scsi_stop(s);
> +        if (ret) {
> +            return ret;
> +        }
>      }
> +    return 0;
>  }
>
>  static void vhost_user_scsi_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> @@ -399,7 +403,7 @@ static void vhost_user_scsi_class_init(ObjectClass *klass, void *data)
>      vdc->unrealize = vhost_user_scsi_unrealize;
>      vdc->get_features = vhost_scsi_common_get_features;
>      vdc->set_config = vhost_scsi_common_set_config;
> -    vdc->set_status = vhost_user_scsi_set_status;
> +    vdc->set_status_ext = vhost_user_scsi_set_status;
>      fwc->get_dev_path = vhost_scsi_common_get_fw_dev_path;
>      vdc->reset = vhost_user_scsi_reset;
>      vdc->get_vhost = vhost_user_scsi_get_vhost;
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 5e8d4cab53..fff7cdb35d 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -2221,12 +2221,12 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val)
>  {
>      VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
>      trace_virtio_set_status(vdev, val);
> +    int ret = 0;
>
>      if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
>          if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
>              val & VIRTIO_CONFIG_S_FEATURES_OK) {
> -            int ret = virtio_validate_features(vdev);
> -
> +            ret = virtio_validate_features(vdev);
>              if (ret) {
>                  return ret;
>              }
> @@ -2238,12 +2238,18 @@ int virtio_set_status(VirtIODevice *vdev, uint8_t val)
>          virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
>      }
>
> -    if (k->set_status) {
> +    if (k->set_status_ext) {
> +        ret = k->set_status_ext(vdev, val);
> +        if (ret) {
> +            qemu_log("set %s status to %d failed, old status: %d\n",
> +                     vdev->name, val, vdev->status);
> +        }
> +    } else if (k->set_status) {
>          k->set_status(vdev, val);
>      }
>      vdev->status = val;
>
> -    return 0;
> +    return ret;
>  }
>
>  static enum virtio_device_endian virtio_default_endian(void)
> @@ -3436,7 +3442,11 @@ static int virtio_vmstate_change(void *opaque, bool running, RunState state)
>      }
>
>      if (!backend_run) {
> -        virtio_set_status(vdev, vdev->status);
> +        // the return value was used for stopping VM during migration
> +        int ret = virtio_set_status(vdev, vdev->status);
> +        if (ret) {
> +            return ret;
> +        }
>      }
>      return 0;
>  }
> diff --git a/include/hw/virtio/vhost-scsi-common.h b/include/hw/virtio/vhost-scsi-common.h
> index c5d2c09455..d54d9c916f 100644
> --- a/include/hw/virtio/vhost-scsi-common.h
> +++ b/include/hw/virtio/vhost-scsi-common.h
> @@ -40,7 +40,7 @@ struct VHostSCSICommon {
>  };
>
>  int vhost_scsi_common_start(VHostSCSICommon *vsc, Error **errp);
> -void vhost_scsi_common_stop(VHostSCSICommon *vsc);
> +int vhost_scsi_common_stop(VHostSCSICommon *vsc);
>  char *vhost_scsi_common_get_fw_dev_path(FWPathProvider *p, BusState *bus,
>                                          DeviceState *dev);
>  void vhost_scsi_common_set_config(VirtIODevice *vdev, const uint8_t *config);
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index 6386910280..c99d56f519 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -187,6 +187,7 @@ struct VirtioDeviceClass {
>      void (*set_config)(VirtIODevice *vdev, const uint8_t *config);
>      void (*reset)(VirtIODevice *vdev);
>      void (*set_status)(VirtIODevice *vdev, uint8_t val);
> +    int (*set_status_ext)(VirtIODevice *vdev, uint8_t val);
>      /* Device must validate queue_index.  */
>      void (*queue_reset)(VirtIODevice *vdev, uint32_t queue_index);
>      /* Device must validate queue_index.  */
> --
> 2.48.1
>
diff mbox series

Patch

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index ae42327cf8..4865786c54 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -204,7 +204,7 @@  err_host_notifiers:
     return ret;
 }
 
-static void vhost_user_blk_stop(VirtIODevice *vdev)
+static int vhost_user_blk_stop(VirtIODevice *vdev)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
@@ -212,26 +212,26 @@  static void vhost_user_blk_stop(VirtIODevice *vdev)
     int ret;
 
     if (!s->started_vu) {
-        return;
+        return 0;
     }
     s->started_vu = false;
 
     if (!k->set_guest_notifiers) {
-        return;
+        return 0;
     }
 
-    vhost_dev_stop(&s->dev, vdev, true);
+    ret = vhost_dev_stop(&s->dev, vdev, true);
 
-    ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
-    if (ret < 0) {
+    if (k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false) < 0) {
         error_report("vhost guest notifier cleanup failed: %d", ret);
-        return;
+        return -1;
     }
 
     vhost_dev_disable_notifiers(&s->dev, vdev);
+    return ret;
 }
 
-static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
+static int vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
     bool should_start = virtio_device_should_start(vdev, status);
@@ -239,11 +239,11 @@  static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
     int ret;
 
     if (!s->connected) {
-        return;
+        return -1;
     }
 
     if (vhost_dev_is_started(&s->dev) == should_start) {
-        return;
+        return 0;
     }
 
     if (should_start) {
@@ -253,9 +253,12 @@  static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
             qemu_chr_fe_disconnect(&s->chardev);
         }
     } else {
-        vhost_user_blk_stop(vdev);
+        ret = vhost_user_blk_stop(vdev);
+        if (ret < 0) {
+            return ret;
+        }
     }
-
+    return 0;
 }
 
 static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
@@ -597,7 +600,7 @@  static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
     vdc->get_config = vhost_user_blk_update_config;
     vdc->set_config = vhost_user_blk_set_config;
     vdc->get_features = vhost_user_blk_get_features;
-    vdc->set_status = vhost_user_blk_set_status;
+    vdc->set_status_ext = vhost_user_blk_set_status;
     vdc->reset = vhost_user_blk_reset;
     vdc->get_vhost = vhost_user_blk_get_vhost;
 }
diff --git a/hw/scsi/vhost-scsi-common.c b/hw/scsi/vhost-scsi-common.c
index 4c8637045d..bfeed0cb1b 100644
--- a/hw/scsi/vhost-scsi-common.c
+++ b/hw/scsi/vhost-scsi-common.c
@@ -101,24 +101,25 @@  err_host_notifiers:
     return ret;
 }
 
-void vhost_scsi_common_stop(VHostSCSICommon *vsc)
+int vhost_scsi_common_stop(VHostSCSICommon *vsc)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(vsc);
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     int ret = 0;
 
-    vhost_dev_stop(&vsc->dev, vdev, true);
+    ret = vhost_dev_stop(&vsc->dev, vdev, true);
 
     if (k->set_guest_notifiers) {
-        ret = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false);
-        if (ret < 0) {
+        int r = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false);
+        if (r < 0) {
                 error_report("vhost guest notifier cleanup failed: %d", ret);
         }
+        assert(r >= 0);
     }
-    assert(ret >= 0);
 
     vhost_dev_disable_notifiers(&vsc->dev, vdev);
+    return ret;
 }
 
 uint64_t vhost_scsi_common_get_features(VirtIODevice *vdev, uint64_t features,
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index adb41b9816..8e7efc38f2 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -52,19 +52,19 @@  static int vhost_user_scsi_start(VHostUserSCSI *s, Error **errp)
     return ret;
 }
 
-static void vhost_user_scsi_stop(VHostUserSCSI *s)
+static int vhost_user_scsi_stop(VHostUserSCSI *s)
 {
     VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
 
     if (!s->started_vu) {
-        return;
+        return 0;
     }
     s->started_vu = false;
 
-    vhost_scsi_common_stop(vsc);
+    return vhost_scsi_common_stop(vsc);
 }
 
-static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
+static int vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserSCSI *s = (VHostUserSCSI *)vdev;
     DeviceState *dev = DEVICE(vdev);
@@ -75,11 +75,11 @@  static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
     int ret;
 
     if (!s->connected) {
-        return;
+        return -1;
     }
 
     if (vhost_dev_is_started(&vsc->dev) == should_start) {
-        return;
+        return 0;
     }
 
     if (should_start) {
@@ -91,8 +91,12 @@  static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
             qemu_chr_fe_disconnect(&vs->conf.chardev);
         }
     } else {
-        vhost_user_scsi_stop(s);
+        ret = vhost_user_scsi_stop(s);
+        if (ret) {
+            return ret;
+        }
     }
+    return 0;
 }
 
 static void vhost_user_scsi_handle_output(VirtIODevice *vdev, VirtQueue *vq)
@@ -399,7 +403,7 @@  static void vhost_user_scsi_class_init(ObjectClass *klass, void *data)
     vdc->unrealize = vhost_user_scsi_unrealize;
     vdc->get_features = vhost_scsi_common_get_features;
     vdc->set_config = vhost_scsi_common_set_config;
-    vdc->set_status = vhost_user_scsi_set_status;
+    vdc->set_status_ext = vhost_user_scsi_set_status;
     fwc->get_dev_path = vhost_scsi_common_get_fw_dev_path;
     vdc->reset = vhost_user_scsi_reset;
     vdc->get_vhost = vhost_user_scsi_get_vhost;
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 5e8d4cab53..fff7cdb35d 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -2221,12 +2221,12 @@  int virtio_set_status(VirtIODevice *vdev, uint8_t val)
 {
     VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
     trace_virtio_set_status(vdev, val);
+    int ret = 0;
 
     if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
         if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
             val & VIRTIO_CONFIG_S_FEATURES_OK) {
-            int ret = virtio_validate_features(vdev);
-
+            ret = virtio_validate_features(vdev);
             if (ret) {
                 return ret;
             }
@@ -2238,12 +2238,18 @@  int virtio_set_status(VirtIODevice *vdev, uint8_t val)
         virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
     }
 
-    if (k->set_status) {
+    if (k->set_status_ext) {
+        ret = k->set_status_ext(vdev, val);
+        if (ret) {
+            qemu_log("set %s status to %d failed, old status: %d\n",
+                     vdev->name, val, vdev->status);
+        }
+    } else if (k->set_status) {
         k->set_status(vdev, val);
     }
     vdev->status = val;
 
-    return 0;
+    return ret;
 }
 
 static enum virtio_device_endian virtio_default_endian(void)
@@ -3436,7 +3442,11 @@  static int virtio_vmstate_change(void *opaque, bool running, RunState state)
     }
 
     if (!backend_run) {
-        virtio_set_status(vdev, vdev->status);
+        // the return value was used for stopping VM during migration
+        int ret = virtio_set_status(vdev, vdev->status);
+        if (ret) {
+            return ret;
+        }
     }
     return 0;
 }
diff --git a/include/hw/virtio/vhost-scsi-common.h b/include/hw/virtio/vhost-scsi-common.h
index c5d2c09455..d54d9c916f 100644
--- a/include/hw/virtio/vhost-scsi-common.h
+++ b/include/hw/virtio/vhost-scsi-common.h
@@ -40,7 +40,7 @@  struct VHostSCSICommon {
 };
 
 int vhost_scsi_common_start(VHostSCSICommon *vsc, Error **errp);
-void vhost_scsi_common_stop(VHostSCSICommon *vsc);
+int vhost_scsi_common_stop(VHostSCSICommon *vsc);
 char *vhost_scsi_common_get_fw_dev_path(FWPathProvider *p, BusState *bus,
                                         DeviceState *dev);
 void vhost_scsi_common_set_config(VirtIODevice *vdev, const uint8_t *config);
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 6386910280..c99d56f519 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -187,6 +187,7 @@  struct VirtioDeviceClass {
     void (*set_config)(VirtIODevice *vdev, const uint8_t *config);
     void (*reset)(VirtIODevice *vdev);
     void (*set_status)(VirtIODevice *vdev, uint8_t val);
+    int (*set_status_ext)(VirtIODevice *vdev, uint8_t val);
     /* Device must validate queue_index.  */
     void (*queue_reset)(VirtIODevice *vdev, uint32_t queue_index);
     /* Device must validate queue_index.  */